The present invention relates generally to the detection of subcutaneous necrosis in order to prevent or arrest development of decubitus ulcers. More specifically, the present invention relates generally to a product that exhibits thermochromic color changes in response to temperature fluctuations on the body to detect the onset of conditions favorable to decubitus ulcers.
Thermochromism is one type of process by which a reversible change in the color of a compound is induced by stimuli. In thermochromism, the stimulus is a change in temperature. Liquid crystals and leuco dyes are the two basic types of compounds typically used in thermochromism. The typical characteristics of liquid crystals include a limited range within which the color can fluctuate supported by a substantially precise response to subtle temperature changes. Leuco dyes have a less accurate response to a temperature fluctuation, but allow a wider range of colors in their application.
As such, depending on the application, liquid crystals or leuco dyes can be used to view a change in the color of a compound induced by a temperature change. For example, leuco dyes are typically used in applications wherein temperature response accuracy is not critical and the subtleties in color change can be overlooked. Conversely, liquid crystals typically are used in applications where the change in temperature and the corresponding change in color can be accurately defined and the application to which they are used require some type of definiteness. As such, liquid crystals are known to have some medical applications including the evaluation of complex pain states associated with arthritis, soft tissue injuries, back pain diseases, and damage to the nervous system.
However, there are difficulties with the use of liquid crystal material in medical applications. Namely, it has been documented that it is difficult to quantify the visual data and correlate that to a prediction of a medical state. It is this quantification, generally related to or dependent on visible recognition, which can be extremely susceptible to observer bias and can lead to improper use or interpretation. A review of liquid crystal technology can be found in “Colourful World Of Liquid Crystals” in the March, 2000 issue of Technology, Volume 3, No. 2.
Additionally, reversible thermochromic materials have been used in personal care products. For example, U.S. Pat. No. 6,290,977, which has since been withdrawn, discloses topical flowable personal care products, and more specifically, a shower gel shampoo, body lotion, moisturizing cream, sunscreen, skin toner, or the like, that exhibits thermochromic color changes in response to body heat or the heat of a bath or shower.
Other studies have directed efforts at infrared skin temperature evaluation in the protection and treatment of ulcers. Namely, a study by Jim Birke titled “Infrared Thermal Thermometry for the High Risk Diabetic Foot” as appearing Feb. 1, 1997 in Physical Therapy, discloses the use of a hand held infrared skin temperature probe to record the differences in skin temperatures between various diabetic ailments. The study focused on predicting the affect of various diabetic ailments by studying both the affected foot and the non-affected foot on those diabetic patients.
Other medical research has been directed at decubitus ulcers, also known as pressure sores or bed sores or pressure ulcers. According to Linda Pershall, R.N., B.S.N., of the LDHP Medical Review Services Corp., decubitus ulcers are preventable and can range from a very mild pink coloration of the skin to a very deep wound extending to and sometimes through internal organs and into the bone. These ulcers are classified according to the severity of the wound and are usually in four stages or types.
The decubitus ulcers are generally formed from pressure or friction caused by pressure on the skin or friction between the skin and another object. The area of tissue that lies just over bone is susceptible to the formation of decubitus ulcers. In the case of pressure as the cause of these ulcers, immobility of a person, such as a debilitated person, is generally the cause. The weight of the person's body presses on the bone which in turn presses on the skin and tissue that cover that bone. That pressure traps the tissue between the bone structure and an outside object, such as a bed, chair or wheelchair and the like, and compresses the blood vessels in the skin and underlying tissues. This pressure causes the tissue to begin to decay from lack of blood circulation.
Additionally, reoccurring friction cause decubitus ulcers. For example, reoccurring movement that causes the skin to rub against an outside object, such as a bed, wheelchair, cast, brace and the like, can damage the small blood vessels and diminish the blood supply to a particular point.
Contributing factors to these ulcers are excess moisture, such as incontinence of the bowels and/or bladder or from perspiration. Additionally, general poor health, undernourishment, obesity, and diabetes can contribute to these ulcers. Poor hygiene and dehydration can also factor in the size and intensity of the ulcers.
The four classifications of the decubitus ulcer are four basic stages with stage one being the earlier mild stages and stage four being the most severe. Stage one represents the stage when the skin is still intact and shows signs of blanchable erythema from reactive hyperemia that typically can resolve itself within 24 hours with the relief of pressure. Increased temperature, such as warmth, and a warming of the skin, and induration is usually present. If the pressure continues, the erythema typically does not blanche with pressure and this can be the first outward sign of tissue destruction. Stage Two represents a partial thickness loss of skin involving the epidermis. This lesion may represent as an abrasion blister or superficial ulceration. Stage Three represents a full thickness loss of skin that extensions into subcutaneous tissue. This lesion appears as a crater that can include undermining of adjacent tissue. Stage four represents a full thickness loss of skin and subcutaneous with an extension into underlying fascia. Obviously it is ideal to detect these types of ulcers in Stage One.
From the inventor's experience as a registered nurse in acute and long-term care facilities and home health, a general theory developed that one explanation for the high rate of decubitus ulcers is poor skin assessment by caregivers. Inpatient facility staff is routinely burdened with an unmanageable number of patients, resulting in a critically limited amount of time per patient for the staff. Some staff may also be unskilled in skin assessments. At-home caregivers also appear to lack both the knowledge and skill to assess skin condition. Additionally, patients with hyper-pigmented skin often face a greater risk of lack of early detection of tissue necrosis because of the difficulty in visually assessing contrasts in skin color. In fact, in 2004, a study of patients in skilled nursing facilities showed a higher prevalence of decubiti in African American patients than white patients leading to the theory that the higher incidence is attributable, at least in part, to the challenge in assessing darker skin.
A cursory literature survey related to prevalence and costs of decubitus ulcers reveals that in the United States, alone, estimates for the occurrence of decubiti run as high as 4.5 million, annually; with up to 25% of that number occurring in the acute care setting. The estimated annual costs for treating decubiti range from $5 to $8.5 billion, excluding costs attributable to the settlement of negligence claims resulting from decubiti. Deaths directly related to decubiti total approximately sixty thousand annually. Again, these figures are for only the United States. Decubiti, however, are a world-wide problem.
According to Dr. Michael Kosiak in Prevention and Rehabilitation of Pressure Ulcers from WouldHEAL.com, 8/04, tissue necrosis can result after only 30-60 minutes of ischemia/pressure and repeated ischemic episodes have a cumulative effect on tissue. He further explains that the “earliest clinical evidence of damage to skin is . . . inflammation . . . which lasts for several hours after the pressure is relieved.” He concludes that the “ability to recognize clinically the development of skin changes involving only the dermis, with its associated inflammatory response, is infinitely more important than (classifying advanced decubiti).”
As previously stated, based on the severity of tissue breakdown/depth of the wound, decubitus ulcers are categorized in four stages. Stage One is the earliest stage, with the most advanced stage, Stage Four, indicating full tissue necrosis and possible damage to muscle and/or bone. Obviously, the greater costs are associated with the more advanced stages. Therefore, one answer to reducing the incidence of the later stages and related costs is the detection of the earliest stage, Stage One. Authors in a study of decubiti in the UK stated, “The focus of attention should be on prevention (of decubiti)—prevention of initial tissue damage, prevention of progression of an ulcer to a more severe grade . . . . ”
Current, commonly practiced prevention techniques include repositioning an immobile patient every two hours to reduce pressure on the same body part, use of airflow beds, and monitoring patients' nutrition. The problems with these methods are that turning and monitoring require strict consistency, which, based on statistical data of occurrence, is not present for most patients. The airflow beds are costly to both facilities and patients and are very limited in use. In one study of 30 patients who developed a total of 45 decubitus ulcers, eighteen were on turning schedules; seventeen had pressure-reducing devices on their beds. For that patient group, the average length of time from detection of the ulcer to healing, for those that did heal, was 116 days—nearly 4 months of treatment and expense and increased care from medical personnel.
What is needed then is a method and product to detect and prevent the onset of decubitus ulcers. This method and product would preferably react to the body and indicate the early stages of decubiti, while providing a readily apparent indication of the same. This needed method and product is lacking in the art.